A tropical summer has left many of us holed up in our air-conditioned homes. Some of us are yet to have our air-conditioning installed, perhaps while waiting for a switchboard upgrade.
For many Australian homes, summer cooling is one of the biggest reasons energy bills rise. This is why more households are asking how solar panels for AC units work, how much rooftop capacity they may need and how to plan a system that supports day-to-day comfort without relying fully on the grid.
When comparing solar panels for AC use, consider factors beyond just the air conditioner. Your roof space, household energy use, insulation, switchboard capacity and daytime power habits can all affect the right system size.
The following guide will outline what to consider in order to maximise your solar system for your air conditioning needs.
Temperature coefficient (Pmax) refers to the amount of panel efficiency lost for every 1°C over 25°C. The general number is 0.5% loss for each 1°C as a standard variable. Skimming a few datasheets, the number tends to be around -0.35%/°C, the closer to 0 the better.
This matters when thinking about solar panels for AC because air conditioning demand is usually highest on hot days, the same conditions that can slightly reduce panel output. A well-planned system should account for real summer conditions, not just ideal tests.
A temperature coefficient less than -0.42%/°C is considered standard. A temperature coefficient at or above -0.38%/°C is considered good.
The best temperature coefficient on the market is around -0.24%/°C.
On a 40° day the worst case is a 6% efficiency loss. This is an estimate as the temperature will change during the day.
If you are wondering, “Can we use a solar panel for AC?” the answer is generally yes. The final result depends on your system size, sunlight, household usage and how long the air conditioner runs each day.
Temperature ratings table showing nominal module operating temperature of 44°C and temperature coefficients for Pmax, Voc, and Isc.
Ensure that your roof is properly insulated and that all air gaps in doorways and windows are addressed.
The first step in sizing your solar system is to determine the power requirements of your air conditioner. This can be a bit tricky, as the power rating of electrical appliances like air conditioners is not always readily available. However, for grid-connected purposes, we are mainly interested in the average power consumption. For example, let’s assume we have a 7kW split system air conditioner with a peak load of 2.5kW. Using some estimation, we can assume an average running load of 2kW.
The next step is to calculate the daily energy consumption of your air conditioner during the hottest days. Simply multiply the average power consumption by the expected running hours. For instance, if your air conditioner runs for 16 hours a day, the daily energy consumption would be 32kWh.
Now, it’s time to determine the energy requirements for the hottest month. To find out the daily kWh energy production per installed kW of solar in the hottest month for your location, you can use the PVWatts website or consult with a solar installer. Let’s assume we have 5.0kWh per day energy production per kilowatt of solar installed during February.
Finally, to calculate the required solar panel capacity, divide your air conditioner’s daily energy consumption by the daily kWh energy production per kilowatt of solar.
In our example, it would be 32kWh divided by 5.0kWh, resulting in a required rooftop solar capacity of 6.4kW. This shows why a solar panel for running AC should be planned with actual usage in mind. A smaller air conditioner used for a few hours a day will place a very different demand on a solar system compared with a large ducted or split system running throughout summer.
It is important to note that this method does not take into account any other household loads. It is solely focused on determining the solar energy requirements to cover air conditioner use during the hottest time of the year in a grid-connected system. Designing a household rooftop solar system involves many other considerations, and it is advisable to consult with a professional installer to ensure the best results for your specific needs.
RenewCo Solar can help assess your home, roof layout and energy usage before recommending the right solar system installation. If you want to store excess solar energy for evening cooling, our team can also discuss solar battery installation and how battery storage may support your air conditioning use after sunset.
Air conditioning can place a heavy load on household energy use, especially during long Australian summers. Solar can help offset that demand, but the best results come from planning the system around how your home actually uses power.
From temperature coefficient and daily running hours to roof space, insulation and battery options, there are several factors that can affect how well solar supports your cooling needs.
RenewCo Solar can help you compare solar panels, system size and battery options for your home. We provide solar services across NSW and can help you understand what may suit your property, energy habits and budget.
Contact RenewCo Solar today to learn more about solar panels for AC, solar system installation, or solar battery installation for your home, or request a quote.
Q: Can solar power effectively run an air conditioning system?
A: Yes, solar power can effectively run an air conditioning system. With advancements in solar technology and the availability of efficient solar panels, it is possible to generate enough electricity from solar energy to power air conditioning units.
Q: Can solar power run air conditioning at night or during cloudy days?
A: Solar power alone may not be sufficient to run an air conditioning system at night or during cloudy days when sunlight is limited. However, energy storage solutions, such as batteries, can be used to store excess solar energy generated during the day and provide power for the air conditioning system when sunlight is not available.
Q: Will solar power be enough to run air conditioning during hot summer days?
A: Solar power can be enough to run air conditioning during hot summer days, especially if the system is properly sized and designed to meet the cooling demands of the space. It is important to consider factors such as the size of the air conditioning unit, insulation levels, and energy efficiency to ensure that the solar power generated is sufficient to meet the cooling needs.
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